Two piece sprocket and pulley wheels adapted for removal from an in place drive shaft in general are well known in the art. Thus, Mills, U.S. Pat. No. 184,540, Nov. 21, 1876 shows a sprocket wheel with a sector dovetailed for axial displacement to expose the driveshaft so that both parts may be removed. This construction has the disadvantages that removal cannot take place in restricted mounting positions without room for axial movement to disassemble the parts, and the dovetail mortise-tenon joint imposes difficult to meet manufacturing tolerances, such that for example, could not easily be attained with inexpensive plastic injection molded parts.
Williams, U.S. Pat. No. 531,820, Jan. 1, 1895 bolts in place a removable sprocket wheel sector just wide enough to move a larger mating portion over the drive shaft. Such smaller sectors tend to unbalance the sprocket wheel, as does the bolting of the small sector to the sprocket wheel rim and hub. Also this construction is only adaptable to a spoked sprocket wheel configuration and requires a significant amount of axial spacing to employ wrenches for disassembly.
Conyngham, U.S. Pat. No. 1,391,719, Sep. 27, 1921 has two half sprockets with circumferential flange extensions about the shaft. The two halves are bolted together through the flange extensions at a hub extending axially away from the sprocket wheel. The bolts also serve to axially lock the wheel in place on the shaft. Not only is the construction of the circumferential flange extensions costly, critical and delicate, but the hub prevents use where side by side sprocket wheels are desired such as in driving modular link belt systems. Also, this construction is inconsistent with the requirement of sprockets in modular link belt drive systems to wander axially on the shaft to conform with dynamic conditions encountered in operation.
Accordingly the prior art has not provided two part sprocket wheels that are readily removable from the shaft of a nature that meets the requirements encountered in a modular link belt drive system. Thus it is an objective to improve the state of the prior art by providing split sprocket wheels particularly adapted for solving the problems encountered in modular link belt drive systems.